netdev - Re: [RFC] ravb: Add support for optional txc

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Date:   Sat, 12 Dec 2020 20:54:58 +0300
From:   Sergei Shtylyov <sergei.shtylyov@...il.com>
To:     Adam Ford <aford173@...il.com>, linux-renesas-soc@...r.kernel.org
Cc:     aford@...conembedded.com, charles.stevens@...icpd.com,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [RFC] ravb: Add support for optional txc_refclk

Hello!

On 12.12.2020 19:56, Adam Ford wrote:

> The SoC expects the txv_refclk is provided, but if it is provided
> by a programmable clock, there needs to be a way to get and enable
> this clock to operate.  It needs to be optional since it's only
> necessary for those with programmable clocks.
> 
> Signed-off-by: Adam Ford <aford173@...il.com>
[...]
> diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
> index bd30505fbc57..4c3f95923ef2 100644
> --- a/drivers/net/ethernet/renesas/ravb_main.c
> +++ b/drivers/net/ethernet/renesas/ravb_main.c
> @@ -2148,6 +2148,18 @@ static int ravb_probe(struct platform_device *pdev)
>   		goto out_release;
>   	}
>   
> +	priv->ref_clk = devm_clk_get(&pdev->dev, "txc_refclk");

    Why not devm_clk_get_optional()?

> +	if (IS_ERR(priv->ref_clk)) {
> +		if (PTR_ERR(priv->ref_clk) == -EPROBE_DEFER) {
> +			/* for Probe defer return error */
> +			error = PTR_ERR(priv->ref_clk);
> +			goto out_release;
> +		}
> +		/* Ignore other errors since it's optional */
> +	} else {
> +		(void)clk_prepare_enable(priv->ref_clk);
> +	}
> +
>   	ndev->max_mtu = 2048 - (ETH_HLEN + VLAN_HLEN + ETH_FCS_LEN);
>   	ndev->min_mtu = ETH_MIN_MTU;
>   

MBR, Sergei